gallium/auxiliary: Extern "c" fixes.

Used by C++ code such as Haiku's renderer.

Reviewed-by: Brian Paul <brianp@vmware.com>

src/gallium/auxiliary/driver_ddebug/dd_public.h

@@ -30,7 +30,15 @@
 
 struct pipe_screen;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct pipe_screen *
 ddebug_screen_create(struct pipe_screen *screen);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* DD_PUBLIC_H_ */

src/gallium/auxiliary/driver_noop/noop_public.h

@@ -23,7 +23,15 @@
 #ifndef NOOP_PUBLIC_H
 #define NOOP_PUBLIC_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct pipe_screen;
 struct pipe_screen *noop_screen_create(struct pipe_screen *screen);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif

src/gallium/auxiliary/target-helpers/inline_debug_helper.h

@@ -16,6 +16,10 @@
 #include "driver_rbug/rbug_public.h"
 #include "driver_noop/noop_public.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*
  * TODO: Audit the following *screen_create() - all of
  * them should return the original screen on failuire.
@@ -35,3 +39,7 @@ debug_screen_wrap(struct pipe_screen *screen)
 }
 
 #endif
+
+#ifdef __cplusplus
+}
+#endif